how can I extrude curve shapes onto curve without tapering
It's a known limitation of the current system, there is currently no elegant workaround for this as far as I know.


Either use only separate 2D curves for each segment (rotate them in object mode to their correct positions)
Add extra control vertex close to corners to minimize the tapering distance (clumsy and may not look good)

Or use independent splines inside the same bezier curve for each segments (may cause intersection artifacts under certain circumstances)



Choose the lesser evil for your particular use case.